Add CI badges

FIX #315

Cargo.toml

@@ -11,6 +11,10 @@ readme = "README.md"
 keywords = ["url", "parser"]
 license = "MIT/Apache-2.0"
 
+[badges]
+travis-ci = { repository = "servo/rust-url" }
+appveyor = { repository = "servo/rust-url" }
+
 [workspace]
 members = [".", "idna", "url_serde"]